# Know It vs Unfog

The clearest difference is update cadence: Unfog at every 2 days against Know It's every 2 months. Know It's advantage is device support (3 vs 1) and iOS requirement (15.1 vs 17.0). On price, ads and in-app purchases there is nothing between them.

Both are free to download. Know It sells 2 in-app purchases, starting at $3.99 per month and Unfog sells 3 in-app purchases, starting at $2.99 per 7 days. Whichever you choose, the download price is not the number that matters.

Know It ships an update every 2 months, Unfog every 2 days. The most recent releases landed on October 15, 2026 and October 25, 2026 respectively.

## The numbers

| Metric | Know It | Unfog |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | Every 2 months | **Every 2 days** |
| Size | 50 MB | 80 MB |
| Requires iOS | **15.1** | 17.0 |
| Devices | **iPhone, iPad, iPod** | iPhone |
| Age rating | 12+ | 4+ |
| Developer | [NOLAN OLIVIER DANIEL ESSERTAIZE](https://appshunter.io/developer/1876489727) | [BITSEC SP. Z O.O.](https://appshunter.io/developer/1801990616) |

## What reviewers say

### Know It

[App page](https://appshunter.io/ios/app/know-it-feynman/id6759038082)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Abonnement étudiant | $3.99 | per month |
| Abonnement Illimité | $12.99 | per month |


### Unfog

[App page](https://appshunter.io/ios/app/unfog-feynman-study-notes/id6776245365)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Unfog weekly | $2.99 | per 7 days |
| Unfog Monthly | $17.99 | per month |
| Unfog Annual | $29.99 | per year |


## Frequently asked questions

### Is Know It free?

Know It is free to download, with in-app purchases available.

### Is Unfog free?

Unfog is free to download, with in-app purchases available.

### Do Know It or Unfog have ads?

Neither Know It nor Unfog shows ads.

### Which is updated more often, Know It or Unfog?

Know It ships an update every 2 months, and Unfog every 2 days. Most recently, Know It was updated on October 15, 2026 and Unfog on October 25, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*